SynTherm® – Insulating Materials SynKraft® KP

SynKraft® KP is a tear resistant, flexible 2-layer insulation made of one layer polyester film and high-compressed pressboard. 

The pressboard absorbs impregnants easily and ensures excellent bonding of all winding components after impregnation. The polyester film improves the electrical and mechanical properties of the pressboard layer of the laminate, in particular the tear resistance, and provides good slip during insertion of windings. The pressboard layer protects the polyester film from damages caused by the lamination stack during processing.

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SynKraft® KP is a very economic slot liner and slot closure in stators and rotors and is also used as layer insulation and covering insulation in small transformers. 


  • Insulation material, class B (130 °C)
  • Insulation acc. to IEC 60626
  • RoHS compliant acc. to 2011/65/EC

Delivery forms

Available thickness μm:

SynKraft® KP is available:

  • tape as of 6 mm width. (depending on thickness)
  • rolls approx. 630 mm or 1.260 mm
  • formats approx 630 mm x 800 mm or approx. 800 mm x 1.260 mm


  • depth approx. 1 - 12 mm, distance approx. 1 - 10 mm
  • from 10 mm to 240 mm width and 0.20 mm thickness

Technical data

Property Unit of measure  
Nominal thickness  mm  0.10
Thickness tolerance  ± 15
Film thickness  µm  50
Specific weight  g/cm²  120
Elongation at break longitudinal  3
Elongation at break transversal  10
Tensile strength longitudinal  N/mm²  100
Tensile strength transversal  N/mm²  70
Property Unit of measure  
Nominal thickness  mm  0.10
Dielectric strength  kV  10